TWI783085B - Sheet material for workpiece processing and method for manufacturing finished workpiece - Google Patents

Abstract

The workpiece processing sheet of the present invention is a workpiece processing sheet comprising: a base material, and an adhesive layer laminated on one side of the base material, wherein the position within the adhesive layer is within a distance from the above-mentioned The surface of the adhesive layer on the opposite side to the base material is a position at a depth of 100 nm, and the oxygen atomic ratio measured by X-ray photoelectron spectroscopy is 20 atomic % or more and 29 atomic % or less. The workpiece processing sheet can suppress water infiltration at the interface between the workpiece processing sheet and the cut object, and at the interface between the workpiece processing sheet and the obtained wafer, and can prevent the semiconductor wafer and the like from being cut. The adhesive originating from the adhesive layer adhering to the cut object when the object is processed is well removed from the cut object by a water flow.

Description

Sheet material for workpiece processing and method for manufacturing finished workpiece

The present invention relates to a workpiece processing sheet that can be preferably used for cutting, and a method for manufacturing a processed workpiece using the workpiece processing sheet.

Semiconductor wafers such as silicon, gallium arsenide, and various packages (hereinafter collectively referred to as "cut objects") are manufactured in a state of large diameter, and then cut (diced) into small element pieces (hereinafter Called "wafer") and after each separation (picking), move to the next step of the adhesion step. At this time, the cut objects such as semiconductor wafers are attached to the workpiece processing sheet with the base material and the adhesive layer, and various steps such as dicing, cleaning, drying, expanding, picking up, and die bonding are performed. .

In the cutting step, the cutting blade, the workpiece, and the workpiece processing sheet are heated by frictional heat generated between the rotating cutting blade, the workpiece, and the workpiece processing sheet. In addition, in the cutting step, cutting pieces are generated from the workpiece or the sheet for workpiece processing, and may adhere to the workpiece.

Therefore, when the cutting step is performed, generally, a water flow is supplied to the cut portion to cool the cutting blade and the like, and at the same time, the generated cutting flakes are removed from the cut object.

Patent Document 1 discloses a workpiece processing sheet for the purpose of promoting the removal of such cutting chips caused by water flow. The surface of the adhesive layer on the opposite side to the base material before ultraviolet irradiation is resistant to pure water. The contact angle is 82°~114°, and the contact angle for diiodomethane is 44°~64°, and the peak value of the probe tack test (probe tack test) of the adhesive layer before ultraviolet irradiation is 294~ 578kPa. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 5019657

[Problem to be Solved by the Invention]

However, in the case of performing the cutting step using the conventional workpiece processing sheet disclosed in Patent Document 1, the adhesive originating from the adhesive layer of the workpiece processing sheet cannot be sufficiently removed from the cut object.

Furthermore, generally due to the supply of water during dicing, water seeps into the interface between the workpiece processing sheet and the cut object, and the interface between the workpiece processing sheet and the obtained wafer. When such infiltration of water occurs, there is a possibility that wafer scattering and wafer chipping may occur.

The present invention has been accomplished in view of the above circumstances, and aims to provide: water infiltration can be suppressed at the interface between the workpiece processing sheet and the cut object, and the interface between the workpiece processing sheet and the obtained wafer, and the A sheet for workpiece processing that adheres to the cut object such as a semiconductor wafer when the adhesive originating from the adhesive layer is well removed from the cut object by water flow, and a sheet using the A method of manufacturing a finished workpiece from a sheet for workpiece processing. [Technical means to solve the problem]

In order to achieve the above object, firstly, the present invention provides a sheet for workpiece processing, which is a sheet for workpiece processing comprising: a base material and an adhesive layer laminated on one side of the base material; it is characterized in that the above-mentioned adhesive Among the positions in the adhesive layer, at a position at a depth of 100 nm from the surface of the adhesive layer opposite to the base material, the atomic ratio of oxygen measured by X-ray photoelectron spectroscopy is 20 atomic % or more and 29 atomic % or more. % or less (invention 1).

In the workpiece processing sheet of the above invention (Invention 1), the ratio of oxygen atoms at a position at a depth of 100 nm from the surface of the adhesive layer opposite to the substrate (hereinafter also referred to as "adhesive surface") is within the above range , the adhesive inside the adhesive layer can be made to have a predetermined affinity for water, whereby the infiltration of water at the interface between the adhesive surface and the cut object and/or the obtained wafer can be suppressed, and water flow can be used to Good removal of adhesive attached to the cut object.

In the above invention (Invention 1), the thickness of the adhesive layer is preferably not less than 1.5 μm and less than 50 μm (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the water contact angle of the surface of the adhesive layer on the opposite side to the substrate is 50° or more and 80° or less (Invention 3).

In the above inventions (Inventions 1 to 3), the adhesive force of the workpiece processing sheet to the silicon wafer was set as F1, and the workpiece processing sheet was immersed in distilled water at 23°C for 12 hours, and then subjected to 24°C at 23°C. When the above-mentioned workpiece processing sheet is set as F2 to the adhesive force of the silicon wafer after drying for 4 hours, the following formula (1) is used: Adhesion reduction rate (%)={(F1-F2)/F1}×100…(1) The calculated adhesive force reduction rate is preferably 20% or more and 50% or less (Invention 4).

In the said invention (invention 4), it is preferable that the said adhesive force F1 is 1000mN/25mm or more and 10000mN/25mm or less (invention 5).

In the above inventions (Inventions 4 and 5), the adhesive force F2 is preferably not less than 900 mN/25mm and not more than 8000 mN/25mm (Invention 6).

In the above inventions (Inventions 1 to 6), it is preferable that the adhesive layer is composed of an active energy ray-curable adhesive (Invention 7).

In the above invention (Invention 7), the active energy ray-curable adhesive is preferably an adhesive composed of an adhesive composition containing an acrylic copolymer containing a compound selected from methyl acrylate, (methyl acrylate, Base) at least one of 2-methoxyethyl acrylate, ethyl carbitol (meth)acrylate, and methoxyethylene glycol (meth)acrylate as a monomer unit constituting the polymer (invention 8).

Among the above inventions (Inventions 1 to 8), a dicing sheet is preferable (Invention 9).

Second, the present invention provides a method of manufacturing a processed workpiece, which is characterized in that it includes: a bonding step, which is to make the above-mentioned adhesive layer of the above-mentioned sheet for workpiece processing (Inventions 1-9) opposite to the above-mentioned base material. The side surface is bonded to the workpiece; the processing step is to process the workpiece on the workpiece processing sheet to obtain a processed workpiece laminated on the workpiece processing sheet; the irradiation step, The above-mentioned adhesive layer is irradiated with active energy rays to harden the above-mentioned adhesive layer, thereby reducing the adhesive force of the above-mentioned workpiece processing sheet to the above-mentioned processed workpiece; The above-mentioned workpiece processing sheet is separated from the above-mentioned processed workpiece (Invention 10). [Invention effect]

The workpiece processing sheet of the present invention can suppress water infiltration at the interface between the workpiece processing sheet and the cut object, and the interface between the workpiece processing sheet and the obtained wafer, and can be cut on a semiconductor wafer or the like. The adhesive derived from the adhesive layer adhering to the cut object during processing of the cut object is well removed from the cut object by the water flow. Moreover, according to the manufacturing method of the processed workpiece of this invention, the processed workpiece can be manufactured efficiently.

Embodiments of the present invention will be described below. [Sheet for workpiece processing] The workpiece processing sheet of this embodiment includes a base material and an adhesive layer laminated on one side of the base material.

1. Physical properties of sheets for workpiece processing In the workpiece processing sheet of this embodiment, the oxygen content measured by X-ray photoelectron spectroscopy is at a position at a depth of 100 nm from the surface of the adhesive layer opposite to the base material in the adhesive layer. The atomic ratio is not less than 20 atomic % and not more than 29 atomic %. Thereby, the adhesive inside the adhesive layer has a predetermined affinity for water. In addition, the details of the measuring method of this oxygen atomic ratio are as described in the test example mentioned later.

Generally, when cutting with a cutting blade, a water flow is supplied to the cutting portion, and at the same time, the rotating cutting blade is brought into contact with the object to cut the object to be cut. At this time, the rotating cutting blade not only touches the object to be cut, but also touches the adhesive layer. The portion touched in this way cuts the adhesive layer, and the adhesive constituting the adhesive layer is rolled up by the cutting blade, resulting in small pieces of the adhesive. The small pieces adhere to the cut object or the formed wafer, which adversely affects the handling of subsequent wafers, or causes deterioration in the quality of the wafer or a product on which the wafer is mounted. Here, since the small pieces of the adhesive are formed as described above, the small pieces exist in the inside of the adhesive layer almost when the adhesive layer is formed.

In the workpiece processing sheet of this embodiment, as described above, since the adhesive inside the adhesive layer has a predetermined affinity for water, even when a small piece of the adhesive adheres to a workpiece or a wafer, the small piece of Surfaces also have an established affinity for water. Therefore, according to the workpiece processing sheet of this embodiment, water infiltration at the interface between the adhesive surface and the workpiece and/or the obtained wafer due to the water flow supplied during dicing can be suppressed, and the water flow can Adhesives adhering to these are removed favorably from cut objects and wafers.

On the other hand, in conventional sheet materials for workpiece processing, the oxygen atomic ratio on the adhesive surface of the adhesive layer tends to increase, and the oxygen atomic ratio inside the adhesive layer tends to decrease due to this phenomenon. One of the reasons for this phenomenon is considered to be that when the adhesive layer is formed using the coating liquid of the adhesive composition, the coating film formed by applying the coating liquid is affected by the moisture in the air. The surface (the surface in contact with the air) tends to concentrate the components with oxygen atoms. In the conventional workpiece processing sheet, since the ratio of oxygen atoms inside the adhesive layer is not sufficiently high, the inside of the adhesive layer does not have sufficient affinity for water. Therefore, the small pieces of adhesive produced from the conventional workpiece processing sheet cannot be well removed from the workpiece or wafer to which they are attached, even with water flow.

If the oxygen atomic ratio is less than 20 atomic %, the adhesive inside the adhesive layer does not have sufficient affinity for water, so that the adhesive pieces cannot be removed from the workpiece or the wafer. In addition, if the above-mentioned oxygen atomic ratio is greater than 29 atomic %, the affinity of the adhesive layer as a whole to water is too high, resulting in occurrence of a problem on the adhesive surface of the adhesive layer, the interface with the cut object and/or the obtained wafer. Water seeps in.

From the point of view that the adhesive attached to the cut object and/or the obtained wafer can be removed well by using water flow, and the water infiltration on the adhesive surface, the interface with the cut object or the wafer can be better suppressed In terms of the workpiece processing sheet according to the present embodiment, the oxygen atomic ratio is preferably 21 atomic % or more. Also, the aforementioned oxygen atomic ratio is preferably 28 atomic % or less.

In addition, in the sheet for workpiece processing of this embodiment, although the ratio of oxygen atoms at a position at a depth of 100 nm from the adhesive surface is specified to be 20 atomic % or more and 29 atomic % or less, it can be presumed that not only the distance from the adhesive surface is a position with a depth of 100 nm, and the adhesive layer also has a predetermined affinity for water for the entire interior of the adhesive layer (except near the adhesive surface). Therefore, when the workpiece processing sheet of this embodiment is used for cutting, regardless of the depth of the rotating cutting blade entering the adhesive layer, the effect of removing the adhesive by water flow and the effect of suppressing the above-mentioned water penetration can be obtained satisfactorily. .

Furthermore, in the workpiece processing sheet according to the present embodiment, the ratio of oxygen atoms measured by X-ray photoelectron spectroscopy on the surface (adhesive surface) opposite to the substrate in the adhesive layer is preferably 29 atoms. % or less, more preferably 28 atomic % or less. Since the oxygen atomic ratio of the adhesive surface is 29 atomic % or less, the affinity of the adhesive surface to water is low. Thereby, the infiltration of water at the interface between the adhesive surface and the cut object and/or the obtained wafer can be effectively suppressed. In addition, in the workpiece processing sheet according to this embodiment, the oxygen atomic ratio of the adhesive surface measured by X-ray photoelectron spectroscopy is preferably 20 atomic % or more, particularly preferably 25 atomic % or more. Since the atomic ratio of oxygen on the adhesive surface is 20 atomic % or more, it becomes easy to adjust the atomic ratio of oxygen at a depth of 100 nm from the adhesive surface to the above range, and it is easy to remove the adhesion on the cut object or Chip adhesive. In addition, the details of the method of measuring the oxygen atomic ratio of the adhesive surface are as described in the test examples described later.

In the workpiece processing sheet of this embodiment, the water contact angle of the surface of the adhesive layer opposite to the substrate is preferably at least 50°, particularly preferably at least 55°, and even more preferably at least 60°. Also, the above-mentioned water contact angle is preferably at most 80°, particularly preferably at most 75°, even more preferably at most 70°. When the above-mentioned water contact angle is 50° or more, the affinity of the adhesive surface to water becomes moderate, and the infiltration of water on the adhesive surface, the interface with the cut object and/or the obtained wafer can be more effectively suppressed. In addition, since the above-mentioned water contact angle is 80° or less, it becomes easy to adjust the ratio of oxygen atoms at a position at a depth of 100 nm from the adhesive surface to the above-mentioned range, and the adhesion on the workpiece or wafer can be easily removed by water flow. of adhesives. In addition, in this specification, a water contact angle means the thing measured before irradiating the active energy ray to the sheet|seat for workpiece|work processing. In addition, the details of the measurement method of the above-mentioned water contact angle are as described in the test examples described later.

For the workpiece processing sheet of this embodiment, the adhesive force of the workpiece processing sheet to the silicon wafer is set to F1, and the workpiece processing sheet is immersed in distilled water at 23°C for 12 hours, and then 24 hours at 23°C. When the adhesive force of the sheet for workpiece processing after drying to the silicon wafer is set as F2, the following formula (1): Adhesion reduction rate (%)={(F1-F2)/F1}×100…(1) The calculated adhesion reduction rate is preferably 20% or more. In addition, the reduction rate of the adhesive force is preferably 50% or less. Since the reduction rate of the adhesive force is 20% or more, even when an adhesive is attached to the cut object, the adhesive force of the adhesive can be moderately reduced by the flow of water, and the adhesive can be removed satisfactorily. In addition, since the reduction rate of the above-mentioned adhesive force is 50% or less, even after the adhesive layer is exposed to water flow, the adhesive force of the adhesive layer to the cut object can be maintained moderately, and the cut object or the obtained The wafers held well on the adhesive layer. In addition, in this specification, both the adhesive force F1 and the adhesive force F2 are the adhesive force measured before irradiating the active energy ray to the sheet|seat for workpiece processing. In addition, the details of the measurement methods of the adhesive force F1 and the adhesive force F2 are as described in the test examples described later.

In the workpiece processing sheet of this embodiment, the above-mentioned adhesive force F1 is preferably at least 1000 mN/25 mm, particularly preferably at least 2000 mN/25 mm, and still more preferably at least 3000 mN/25 mm. In addition, the adhesive force F1 is preferably not more than 10000 mN/25mm, particularly preferably not more than 7000 mN/25mm.

Furthermore, in the workpiece processing sheet of this embodiment, the above-mentioned adhesive force F2 is preferably 900 mN/25 mm or more, particularly preferably 1500 mN/25 mm or more, more preferably 2000 mN/25 mm or more. In addition, the adhesive force F2 is preferably not more than 8000 mN/25 mm, particularly preferably not more than 5000 mN/25 mm.

When the adhesive force F1 and the adhesive force F2 are respectively within the above-mentioned ranges, it becomes possible to easily adjust the adhesive force reduction rate to the above-mentioned range.

2. Constituent components of sheets for workpiece processing (1) Substrate In the workpiece processing sheet of the present embodiment, as long as the base material exhibits a desired function in the use step of the workpiece processing sheet, it is preferable that the substrate exhibits good penetration of the active energy rays irradiated to harden the adhesive layer. Permeability is not particularly limited.

For example, the base material is preferably a resin film based on a resin-based material. As its specific example, for example: ethylene-vinyl acetate copolymer film; ethylene-(meth)acrylic acid copolymer film, ethylene-( Ethylene-based copolymer films such as methyl methacrylate copolymer films and other ethylene-(meth)acrylate copolymer films; polyethylene films, polypropylene films, polybutene films, polybutadiene films, poly Polyolefin-based films such as methylpentene film, ethylene-norcamphene copolymer film, and norbornene resin film; polyvinyl chloride-based films such as polyvinyl chloride film and vinyl chloride copolymer film; polyethylene terephthalate Polyester film, polybutylene terephthalate film, polyethylene naphthalate and other polyester films; (meth)acrylate copolymer film; polyurethane film; polyimide film; polystyrene film; Polycarbonate film; Fluorine resin film, etc. As an example of a polyethylene film, a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, a high-density polyethylene (HDPE) film, etc. are mentioned. In addition, modified films such as these crosslinked films and ionic polymer films can also be used. In addition, the base material may be a laminated film obtained by laminating a plurality of the above-mentioned films. In this laminated film, the materials constituting each layer may be of the same kind or different kinds. Among the above-mentioned films, it is preferable to use an ethylene-methyl methacrylate copolymer film from the viewpoint of excellent flexibility as the base material. In addition, "(meth)acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

The base material may also contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. The content of these additives is not particularly limited, but is preferably set within a range in which the substrate can exhibit desired functions.

For the surface of the laminated adhesive layer of the substrate, in order to improve the adhesion with the adhesive layer, surface treatments such as primer treatment, corona treatment, and plasma treatment can also be performed.

The thickness of the base material can be appropriately set according to the method used for the workpiece processing sheet, but usually it is preferably 20 μm or more, and particularly preferably 25 μm or more. In addition, the thickness is usually preferably not more than 450 μm, particularly preferably not more than 300 μm.

(2) Adhesive layer In the workpiece processing sheet of the present embodiment, the adhesive layer is not particularly limited as long as it can exert the desired adhesive force on the workpiece and achieve the aforementioned oxygen atomic ratio at a position at a depth of 100 nm from the adhesive surface. limited.

The adhesive constituting the adhesive layer may be an active energy ray-curable adhesive or an active energy ray non-curable adhesive, but is preferably an active energy ray-curable adhesive. Since the adhesive layer is composed of an active energy ray-curable adhesive, the adhesive layer is cured by irradiation with active energy rays when separating the cut object attached to the adhesive surface of the adhesive layer from the adhesive surface. , and can reduce the adhesion of the workpiece processing sheet to the cut object. This facilitates separation of the adhesive surface of the adhesive layer from the cut object.

The active energy ray-curable adhesive constituting the adhesive layer may be composed of an active energy ray-curable polymer as the main component, or may be an active energy ray non-curable polymer (non-active energy ray-curable polymer). polymer) and a mixture of monomers and/or oligomers having at least one active energy ray-curable group as the main component. Also, a mixture of an active energy ray curable polymer and an active energy ray non-curable polymer may be used. Also, it may be a mixture of a polymer having active energy ray curability and a monomer and/or oligomer having at least one active energy ray curable group. Furthermore, it may be a mixture of an active energy ray curable polymer, an active energy ray non-curable polymer, and a monomer and/or oligomer having at least one active energy ray curable group.

First, the case where the active energy ray-curable adhesive contains an active energy ray-curable polymer as a main component will be described below.

The active energy ray curable polymer is preferably a (meth)acrylate (co)polymer (A) ( Hereinafter, it is also referred to as "active energy ray-curable polymer (A)"). The active energy ray-curable polymer (A) is preferably obtained by reacting an acrylic copolymer (a1) having a functional group-containing compound (a2) with an unsaturated group-containing compound (a2). monomer unit, the unsaturated group-containing compound (a2) has a functional group bonded to the functional group.

The acrylic copolymer (a1) preferably contains a monomer for adjusting the hydrophilicity of the acrylic copolymer (a1) as a monomer unit constituting the polymer (hereinafter also referred to as "hydrophilicity adjusting monomer"), In particular, as a specific example thereof, it is preferable to contain a compound selected from methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, and methyl (meth)acrylate. at least one of oxyethylene glycol esters.

By using the above-mentioned hydrophilicity adjusting monomer, it became possible to easily adjust the oxygen atomic ratio at a position at a depth of 100 nm from the adhesive surface to the aforementioned range. As this reason, the following two are considered. However, the reasons are not limited to these two, and there are cases where it is not these two.

As a first reason, many of the above-mentioned hydrophilicity adjusting monomers have many oxygen atoms, and by using the acrylic copolymer (a1) composed of the monomers, the absolute amount of oxygen atoms in the adhesive layer It will also increase, and it becomes possible to easily adjust the ratio of oxygen atoms at a position at a depth of 100 nm from the adhesive surface to the aforementioned range.

As the second reason, it is possible to control the concentration of oxygen atoms in the adhesive layer by using the above-mentioned hydrophilicity adjusting monomer, thereby making it possible to easily release oxygen at a position 100 nm deep from the adhesive surface. The atomic ratio is adjusted to the aforementioned range. In general, when an adhesive layer is formed using a coating solution of an adhesive composition, due to the influence of moisture present in the air, the surface of the coating film formed by applying the coating solution (where it comes into contact with the air) Surface), there is a tendency to concentrate the composition of oxygen atoms. For example, when the acrylic copolymer (a1) contains 2-hydroxyethyl acrylate described later as a constituent monomer, the portion derived from the monomer tends to be localized on the surface. However, since the acrylic copolymer (a1) contains the above-mentioned hydrophilicity adjusting monomer, components having oxygen atoms (2-hydroxyethyl acrylate, hydrophilicity adjusting monomer, etc.) are uniformly present in the coating film, and as a result The ratio of oxygen atoms at a position at a depth of 100 nm from the adhesive surface can be easily adjusted to the aforementioned range.

From the viewpoint of being able to easily adjust the ratio of oxygen atoms at a position at a depth of 100 nm from the adhesive surface to the aforementioned range, the acrylic copolymer (a1), as a monomer unit constituting the polymer, is composed of the above-mentioned hydrophilicity adjusting monomer Among them, it is preferable to contain at least one of methyl acrylate, 2-methoxyethyl acrylate, and methoxyethylene glycol acrylate.

When the acrylic copolymer (a1) contains methyl acrylate as a monomer unit constituting the polymer, the content of methyl acrylate is preferably at least 10% by mass, particularly preferably at least 20% by mass, and still more preferably at least 30% by mass. %above. Also, the content of methyl acrylate is preferably 85% by mass or less. By setting these contents, the atomic ratio of oxygen at a position at a depth of 100 nm from the adhesion surface can be easily adjusted to the aforementioned range. In addition, in this specification, content (mass %) of the said (meth)acrylate alkoxylate means content with respect to the total monomer which comprises an acrylic-type copolymer (a1). Moreover, content (mass %) of the other monomer mentioned later also means content with respect to the total monomer which comprises an acrylic-type copolymer (a1).

Furthermore, in the case where the acrylic copolymer (a1) contains 2-methoxyethyl acrylate as a monomer unit constituting the polymer, the content of 2-methoxyethyl acrylate is preferably 10% by mass. Above, particularly preferably at least 20% by mass, even more preferably at least 30% by mass. Also, the content of 2-methoxyethyl acrylate is preferably at most 85% by mass, particularly preferably at most 80% by mass, and still more preferably at most 70% by mass. By setting these contents, the atomic ratio of oxygen at a position at a depth of 100 nm from the adhesion surface can be easily adjusted to the aforementioned range.

Furthermore, when the acrylic copolymer (a1) contains both methyl acrylate and 2-methoxyethyl acrylate as monomer units constituting the polymer, methyl acrylate and 2-methoxyethyl acrylate The total value of the ester content is preferably at least 10% by mass, particularly preferably at least 30% by mass, and most preferably at least 50% by mass. Moreover, the above-mentioned total value is preferably at most 90% by mass, particularly preferably at most 85% by mass. By setting the above-mentioned total value to these ranges, it becomes possible to easily adjust the oxygen atomic ratio at a position at a depth of 100 nm from the adhesion surface to the above-mentioned range.

Furthermore, when the acrylic copolymer (a1) contains methoxyethylene glycol acrylate as a monomer unit constituting the polymer, the content of methoxyethylene glycol acrylate is preferably 10% by mass or more, especially Preferably, it is at least 30% by mass. Also, the content of methoxyethylene glycol acrylate is preferably at most 90% by mass, particularly preferably at most 85% by mass. By setting these contents, the atomic ratio of oxygen at a position at a depth of 100 nm from the adhesion surface can be easily adjusted to the aforementioned range.

The acrylic copolymer (a1) preferably contains a structural unit derived from a functional group-containing monomer in addition to the above-mentioned hydrophilicity adjusting monomer.

The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) is preferably a mixture of a polymerizable double bond in the molecule and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group. monomer.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (methyl) ) 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like can be used alone or in combination of two or more.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more.

As an amino group-containing monomer or a substituted amino group-containing monomer, aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. are mentioned, for example. These may be used alone or in combination of two or more.

The acrylic copolymer (a1) preferably contains 1% by mass or more of the structural unit derived from the functional group-containing monomer, particularly preferably 5% by mass or more, and more preferably 10% by mass or more. Moreover, the acrylic copolymer (a1) preferably contains 35% by mass or less of the structural unit derived from the above-mentioned functional group-containing monomer, particularly preferably 30% by mass or less.

Furthermore, the acrylic copolymer (a1), in addition to the above-mentioned monomers, may also contain structural units derived from (meth)acrylate monomers other than methyl acrylate or derivatives thereof (hereinafter also referred to as " any monomer").

As the above-mentioned (meth)acrylate monomer, an alkyl (meth)acrylate having an alkyl group of 1 to 20 carbon atoms can be preferably used. In addition, for example, a monomer having an alicyclic structure in the molecule can also be used. Body (monomer containing alicyclic structure).

As the alkyl (meth)acrylate, an alkyl (meth)acrylate having an alkyl group of 1 to 18 carbon atoms can be used particularly preferably, for example: methyl methacrylate, ethyl (meth)acrylate, Among them, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferable from the viewpoint of ease of adjustment of adhesive properties. Use n-butyl (meth)acrylate. These may be used alone or in combination of two or more.

As monomers containing an alicyclic structure, for example, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate, (meth) Isocamphoryl acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and the like. These may be used alone or in combination of two or more.

When the acrylic copolymer (a1) contains the above-mentioned arbitrary monomers, the acrylic copolymer (a1) preferably contains 50 mass % or more of the above-mentioned arbitrary monomers, particularly preferably contains 60 mass % or more, further preferably contains More than 70% by mass. Moreover, it is preferable that an acryl-type copolymer (a1) contains 99 mass % or less of said arbitrary monomers, it is especially preferable that it contains 95 mass % or less, and it is still more preferable that it contains 90 mass % or less.

The acrylic copolymer (a1) is preferably obtainable by copolymerizing the above-mentioned hydrophilicity-adjusting monomer, functional group-containing monomer, and optional monomers if necessary, by a conventional method. In addition, dimethyl acrylamide, vinyl formate, vinyl acetate, styrene, etc. can also be copolymerized.

Active energy ray curing can be obtained by reacting the acrylic copolymer (a1) having the above-mentioned functional group-containing monomer unit with the unsaturated group-containing compound (a2) having a functional group bonded to the functional group. Sexual polymer (A).

The functional group which the unsaturated group containing compound (a2) has can be selected suitably according to the kind of the functional group of the functional group containing monomeric unit which the acrylic-type copolymer (a1) has. For example, in the case where the functional group contained in the acrylic copolymer (a1) is a hydroxyl group, an amino group, or a substituted amino group, the functional group contained in the unsaturated group-containing compound (a2) is preferably an isocyanate group or a ring. In the case of the functional group of the acrylic copolymer (a1) being an epoxy group, the functional group of the unsaturated group-containing compound (a2) is preferably an amine group, a carboxyl group, or an aziridine group. base.

Furthermore, the above-mentioned unsaturated group-containing compound (a2) contains at least one active energy ray polymerizable carbon-carbon double bond in one molecule, preferably 1 to 6, more preferably 1 to 4 . Specific examples of such an unsaturated group-containing compound (a2) include, for example, 2-methacryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate , methacryl isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl) ethyl isocyanate; from diisocyanate compounds or polyisocyanate compounds, and (meth)acrylic acid Acryl monoisocyanate compound obtained by reacting hydroxyethyl ester; acryl monoisocyanate compound obtained by reacting diisocyanate compound or polyisocyanate compound, polyol compound, and (meth)hydroxyethyl acrylate; Glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2-oxazoline, 2-isopropene Base-2-oxazoline, etc.

The above-mentioned unsaturated group-containing compound (a2) is preferably 50 mole % or more, particularly preferably 60 mole %, relative to the number of moles of the functional group-containing monomer of the above-mentioned acrylic copolymer (a1). % or more, preferably more than 70 mole %. Furthermore, the above-mentioned unsaturated group-containing compound (a2) is preferably 95 mole % or less, particularly preferably 93 It is less than 90 mole %, preferably at a ratio of less than 90 mole %.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) can be The combination of reaction temperature, pressure, solvent, time, presence of catalyst, and catalyst type are appropriately selected. Thereby, the functional group present in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group is introduced into the side of the acrylic copolymer (a1). chain to obtain an active energy ray-curable polymer (A).

The weight average molecular weight (Mw) of the active energy ray-curable polymer (A) thus obtained is preferably at least 10,000, particularly preferably at least 150,000, and still more preferably at least 200,000. In addition, the weight average molecular weight (Mw) is preferably at most 1,500,000, particularly preferably at most 1,000,000. In addition, the weight average molecular weight (Mw) in this specification is the standard polystyrene conversion value measured by the gel permeation chromatography (GPC method).

Even when the active energy ray-curable adhesive is mainly composed of active energy ray-curable polymers such as the active energy ray-curable polymer (A), the active energy ray-curable adhesive may further contain active energy ray-curable adhesives. Energy ray curable monomer and/or oligomer (B).

As the active energy ray-curable monomer and/or oligomer (B), for example, an ester of a polyhydric alcohol and (meth)acrylic acid or the like can be used.

Examples of the active energy ray-curable monomer and/or oligomer (B) include monofunctional acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate; Trimethylolpropane Tri(meth)acrylate, Neopentylthritol Tri(meth)acrylate, Neopentylthritol Tetra(meth)acrylate, Dineopentylthritol Hexa(meth)acrylate, 1,4-Butanediol Di(meth)acrylate, 1,6-Hexanediol Di(meth)acrylate, Polyethylene Glycol Di(meth)acrylate, Dimethyloltricyclodecane Polyfunctional acrylates such as di(meth)acrylates; polyester oligomeric (meth)acrylates, polyurethane oligomeric (meth)acrylates, etc.

When the active energy ray-curable polymer (A) is blended with an active energy ray-curable monomer and/or oligomer (B), the active energy ray-curable adhesive in the active energy ray-curable adhesive The content of the monomer and/or oligomer (B) is preferably greater than 0 parts by mass, particularly preferably 60 parts by mass or more, based on 100 parts by mass of the active energy ray-curable polymer (A). Moreover, this content is preferably 250 mass parts or less with respect to 100 mass parts of active energy ray-curable polymer (A), especially preferably 200 mass parts or less.

Here, in the case of using ultraviolet rays as active energy rays for hardening the active energy ray-curable adhesive, it is preferable to add a photopolymerization initiator (C), by using this photopolymerization initiator (C ), which can reduce the polymerization hardening time and light exposure.

、1-羥環己基苯酮、苄基二苯硫醚、單硫化四甲胺硫甲醯、偶氮雙異丁腈、苄基、二苄基、二乙醯基、β-氯化蒽醌、(2,4,6-三甲基苄基二苯基)氧化膦、2-苯并噻唑基-N,N-二乙基二硫胺基甲酸酯、寡聚{2-羥-2-甲基-1-[4-(1-丙烯基)苯基]丙酮}、2,2-二甲氧基-1,2-二苯基乙烷-1-酮等。該等可單獨使用，亦可併用二種以上。Specific examples of the photopolymerization initiator (C) include diphenyl ketone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin Isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4-diethyloxysulfur

, 1-hydroxycyclohexyl benzophenone, benzyl diphenyl sulfide, tetramethylammonium thioformyl monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-anthraquinone chloride , (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazolyl-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2 -Methyl-1-[4-(1-propenyl)phenyl]acetone}, 2,2-dimethoxy-1,2-diphenylethan-1-one, etc. These may be used alone or in combination of two or more.

Photopolymerization initiator (C) with respect to active energy ray curable polymer (A) (in the case of blending active energy ray curable monomer and/or oligomer (B), active energy ray curable The total amount of the polymer (A) and the active energy ray-curable monomer and/or oligomer (B) is 100 parts by mass) 100 parts by mass, preferably 0.1 part by mass or more, particularly preferably 0.5 part by mass Use the above amount. Also, the photopolymerization initiator (C) is active energy ray-curable polymer (A) (in the case of blending active energy ray-curable monomer and/or oligomer (B), the active energy ray The total amount of curable polymer (A) and active energy ray curable monomer and/or oligomer (B) is 100 parts by mass) 100 parts by mass, preferably 10 parts by mass or less, particularly preferably 6 parts by mass It is used in an amount of less than parts by mass.

In the active energy ray-curing adhesive, other components may be appropriately blended in addition to the above-mentioned components. As other components, an active energy ray non-curable polymer component or an oligomer component (D), a crosslinking agent (E), etc. are mentioned, for example.

Examples of active energy ray non-hardening polymer components or oligomer components (D) include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., preferably with a weight average molecular weight (Mw) of 30-2.5 million polymers or oligomers. By blending this component (D) into the active energy ray-curable adhesive, the adhesiveness and peelability before curing, the strength after curing, the adhesiveness with other layers, the storage stability, and the like can be improved. The compounding quantity of this component (D) is not specifically limited, It is determined suitably within the range of more than 0 mass part and 50 mass parts or less with respect to 100 mass parts of active energy ray curable polymer (A).

As the crosslinking agent (E), a polyfunctional compound reactive with a functional group contained in the active energy ray-curable polymer (A) or the like can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, Metal chelate compounds, metal salts, ammonium salts, reactive phenolic resins, etc.

The blending amount of the crosslinking agent (E) is preferably at least 0.01 parts by mass, particularly preferably at least 3 parts by mass, based on 100 parts by mass of the active energy ray-curable polymer (A). Moreover, the compounding quantity of a crosslinking agent (E) is preferably 20 mass parts or less with respect to 100 mass parts of active energy ray-curable polymer (A), Especially preferably, it is 17 mass parts or less.

Next, for the case where the active energy ray-curable adhesive is mainly composed of a mixture of active energy ray non-curable polymer components and monomers and/or oligomers having at least one active energy ray-curable group ,described as follows.

As the active energy ray non-curing polymer component, for example, the same component as that of the above-mentioned acrylic copolymer (a1) can be used.

As the monomer and/or oligomer having at least one active energy ray-curing group, the same ones as those of the above-mentioned component (B) can be selected. The blending ratio of the active energy ray non-curable polymer component and the monomer and/or oligomer having at least one active energy ray-curable group relative to 100 parts by mass of the active energy ray non-curable polymer component , preferably at least 1 part by mass of monomers and/or oligomers having at least one active energy ray-curable group, particularly preferably at least 60 parts by mass. Also, the blending ratio is preferably 200 parts by mass or less of the monomer and/or oligomer having at least one active energy ray-curable group relative to 100 parts by mass of the active energy ray non-curable polymer component. , preferably 160 parts by mass or less.

Even in this case, the photopolymerization initiator (C) and the crosslinking agent (E) may be appropriately blended as described above.

In the workpiece processing sheet of this embodiment, the oxygen atom ratio at a position 100 nm deep from the adhesive surface among the positions in the adhesive layer is regulated as described above, so the thickness of the adhesive layer is naturally 100 nm or more. In particular, the adhesive layer is preferably at least 1.5 μm, particularly preferably at least 2 μm. Also, the thickness is preferably 50 μm or less, particularly preferably 40 μm or less. When the thickness of the adhesive layer is in the above-mentioned range, it becomes possible to easily achieve the desired adhesive force with respect to the cut object.

(3) Peeling sheet In the workpiece processing sheet of this embodiment, a release sheet may be laminated on the surface for the purpose of protecting the surface until the adhesive surface of the adhesive layer is attached to the workpiece. The structure of the peeling sheet is optional, and one in which a plastic film is peeled with a peeling agent or the like is exemplified. Specific examples of plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; and polyolefin films such as polypropylene and polyethylene. . As the release agent, polysiloxane-based, fluorine-based, long-chain alkyl-based, etc. can be used, and among them, polysiloxane-based, which is inexpensive and can obtain stable performance, is preferable. The thickness of the release sheet is not particularly limited, but is usually not less than 20 μm and not more than 250 μm.

(4) Other components In the workpiece processing sheet of this embodiment, an adhesive layer may be laminated on the adhesive surface of the adhesive layer. In this case, the sheet for workpiece processing of this embodiment can be used as a dicing/die bonding sheet by having an adhesive layer as described above. This kind of workpiece processing sheet sticks a cut object on the surface of the adhesive layer that is opposite to the adhesive layer, and cuts the cut object together with the adhesive layer, thereby obtaining a laminated material Singularized adhesive layer wafers. The chip can be easily fixed on the object carried by the chip through the singulated adhesive layer. As the material constituting the adhesive layer, those containing thermoplastic resin and low-molecular-weight thermosetting adhesive components, those containing B-stage (semi-cured) thermosetting adhesive components, and the like are preferably used.

Furthermore, in the workpiece processing sheet of this embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the workpiece processing sheet of this embodiment can be used as a protective film forming and dicing sheet. In this type of workpiece processing sheet, a cut object is attached to the surface of the protective film forming layer opposite to the adhesive layer, and the cut object is cut together with the protective film forming layer to obtain a laminate. A wafer with a singulated protective film forming layer. As the cut object, one having a circuit formed on one surface is preferably used, and in this case, a protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. By hardening the singulated protective film formation layer in a predetermined sequence, a protective film with sufficient durability can be formed on the wafer. The protective film forming layer is preferably composed of an uncured curable adhesive.

In addition, the sheet for workpiece processing according to the embodiment of the present invention satisfies the above-mentioned water contact angle and adhesive force reduction rate. In the case of laminating the above-mentioned adhesive layer or protective film forming layer on the adhesive layer, the lamination of these layers The previous adhesive layer may have an oxygen atom ratio at a position at a depth of 100 nm from the adhesive surface satisfying the aforementioned range.

3. Manufacturing method of sheet for workpiece processing The manufacturing method of the workpiece processing sheet of this embodiment is not particularly limited, but it is preferable that the workpiece processing sheet of this embodiment is manufactured by laminating an adhesive layer on one side of a base material.

Lamination of the adhesive layer on one side of the substrate can be performed by a known method. For example, it is preferable to transfer the pressure-sensitive adhesive layer formed on the release sheet to one side of the substrate. In this case, an adhesive composition constituting the adhesive layer, and a coating solution containing a solvent or a dispersion medium if necessary, are prepared, and applied to the release-treated surface (hereinafter also referred to as "release surface") of the release sheet, Using a die coater, curtain coater, spray coater, slit coater, blade coater, etc., the coating liquid is applied to form a coating film, and the coating film is dried, thereby An adhesive layer may be formed. The properties of the coating liquid are not particularly limited as long as it can be applied, and may contain components for forming an adhesive layer as a solute or as a dispersoid. The release sheet in this laminate can be peeled off as a step material, and can also be used to protect the adhesive surface of the adhesive layer until the workpiece processing sheet is attached to the cut object.

In the case where the coating solution for forming the adhesive layer contains a cross-linking agent, it is only necessary to harden the active energy rays in the coating film by changing the above-mentioned drying conditions (temperature, time, etc.), or by otherwise devising heat treatment The polymer (A) or the active energy ray non-hardening polymer may undergo a crosslinking reaction with a crosslinking agent to form a crosslinked structure at a desired density in the adhesive layer. In order to make the cross-linking reaction fully proceed, after laminating the adhesive on the substrate by the above-mentioned method, etc., the obtained workpiece processing sheet can also be left to stand in an environment of, for example, 23°C and a relative humidity of 50%. Ripening is carried out in a few days.

Instead of transferring the adhesive layer formed on the release sheet to one side of the base material as described above, the adhesive layer may be directly formed on the base material. In this case, the aforementioned coating solution for forming the adhesive layer is applied to one side of the substrate to form a coating film, and the coating film is dried to form the adhesive layer.

4. How to use sheet for workpiece processing The workpiece processing sheet of this embodiment is used for processing a workpiece (cutting object). That is, after adhering the adhesive surface of the workpiece processing sheet of this embodiment to the workpiece, the workpiece can be processed on the workpiece processing sheet. According to this processing, the workpiece processing sheet of this embodiment can be used as a back grinding sheet, a dicing sheet, a mesh sheet, a pick-up sheet, and the like. Here, examples of the cut object include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

Furthermore, when the workpiece processing sheet of this embodiment is equipped with the said adhesive layer, this workpiece processing sheet can be used as a dicing/bonding wafer. Moreover, when the sheet for workpiece processing of this embodiment is provided with the said protective film formation layer, this sheet for workpiece processing can be used as a sheet for protective film formation and dicing.

In the workpiece processing sheet of this embodiment, even when the adhesive originating from the adhesive layer adheres to the workpiece, the adhesive can be easily removed by water flow, and it is possible to suppress the adhesion of the workpiece processing sheet. The infiltration of water by the flow of water occurs at the interface with the workpiece and the interface between the workpiece processing sheet and the obtained wafer. Therefore, the workpiece processing sheet of the present embodiment is suitable for processing using a water flow, and is particularly suitable for cutting while supplying a water flow to the cut portion. That is, the sheet for workpiece processing of this embodiment is suitably used as a dicing sheet.

When using the workpiece processing sheet of this embodiment as a cutting sheet, general conditions can be used as cutting conditions and water flow supply conditions. In particular, regarding the supply conditions of the water flow, it is preferable to use pure water or the like as the water used. The amount of water supplied is preferably at least 0.5 L/min, particularly preferably at least 1 L/min. Also, the supply rate of water is preferably 2.5 L/min or less, particularly preferably 2 L/min or less. Moreover, the temperature of water is not specifically limited, For example, it is preferable to set it as about room temperature.

[Manufacturing method of processed workpiece] A method for manufacturing a processed workpiece according to an embodiment of the present invention includes: a bonding step of bonding the surface of the adhesive layer of the workpiece processing sheet opposite to the base material to the workpiece; a processing step of In this method, a processed workpiece laminated on the workpiece processing sheet is obtained by processing the workpiece on the workpiece processing sheet; in the irradiation step, the adhesive layer is irradiated with active energy rays to harden the adhesive layer, and reducing the adhesive force of the workpiece processing sheet to the processed workpiece; and, in the separating step, separating the processed workpiece from the workpiece processing sheet after the active energy ray irradiation.

The workpiece processing sheet used in the manufacturing method of the processed workpiece of this embodiment can suppress the infiltration of water at the interface between the workpiece processing sheet and the workpiece or the processed workpiece, and can be well removed by water flow. Adhesive attached to the workpiece during processing. Therefore, according to the manufacturing method of the processed workpiece of this embodiment, the processed workpiece can be manufactured efficiently.

Hereinafter, each step of the manufacturing method of the machined workpiece of this embodiment is demonstrated.

(1) Fitting step The bonding of the workpiece and the sheet for workpiece processing in the bonding step can be performed by a conventionally known method. In addition, when the workpiece is cut in the subsequent processing step, it is preferable to bond the ring frame to the outer peripheral region of the region bonded to the workpiece in the surface of the sheet for processing the workpiece on the adhesive layer side. Also, the workpiece to be used may be a desired one depending on the processed workpiece to be manufactured, and as a specific example, the aforementioned ones can be used.

(2) Processing steps In the processing step, desired processing can be performed on the workpiece, for example, back grinding, cutting, and the like can be performed. Such processing can be performed by a conventionally known method.

In addition, when blade cutting using a rotating blade is performed as the above-mentioned processing, generally, the workpiece is cut together with a part of the adhesive layer in the workpiece processing sheet. At this time, the adhesive constituting the adhesive layer may be rolled up by the blade and adhere to the processed workpiece. However, the workpiece processing sheet used in the manufacturing method of the processed workpiece according to this embodiment can well remove the adhered adhesive by water flow as described above. From this point of view, the processing in this embodiment is suitable for dicing, and is particularly suitable for blade dicing using a rotary blade.

(3) Irradiation steps In the irradiation step, as long as the adhesive force of the workpiece processing sheet to the processed workpiece can be reduced to a desired level, the irradiation conditions of active energy rays are not limited, and can be performed based on conventionally known methods. The type of active energy rays to be used includes, for example, ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, etc., and among them, ultraviolet rays that are easily introduced into irradiation equipment are preferred.

(4) Separation step The separation step is performed by separating according to the type of processing and the method of obtaining the processed workpiece. For example, when dicing is performed as processing to obtain wafers in which workpieces are separated into pieces by the dicing, the obtained wafers are picked up one by one from a workpiece processing sheet using a conventionally known pick-up device. In addition, in order to facilitate this pick-up, the sheet for workpiece processing may be formed into a mesh, and the processed workpieces may be separated from each other.

(5) Others The manufacturing method of the machined workpiece of this embodiment can also design steps other than the above steps. For example, after the bonding step, a transport step of transporting the laminate of the obtained workpiece and workpiece processing sheet to a predetermined position, a storage step of storing the laminate for a predetermined period, etc. may be designed. In addition, after the separating step, an adhering step of adhering the obtained processed workpiece to a predetermined substrate or the like may be designed.

The embodiments described above are described for easy understanding of the present invention, and are not described for limiting the present invention. Therefore, the requirements disclosed in the above-mentioned embodiments also include all design changes and equivalents belonging to the technical scope of the present invention.

For example, another layer is provided between the base material and the adhesive layer, or on the surface of the base material opposite to the adhesive layer. [Example]

Hereinafter, the present invention will be described more concretely using examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1] (1) Preparation of adhesive composition The acrylic copolymer obtained by copolymerizing 80 parts by mass of methyl acrylate and 20 parts by mass of 2-hydroxyethyl acrylate is 21.4 g (relative to 2-hydroxyethyl acrylate) for 100 g of the acrylic copolymer The number of moles of ethyl ester, equivalent to 80 mole %) of methacryloxyethyl isocyanate (MOI) is reacted to obtain an active energy ray curable polymer. When the weight average molecular weight (Mw) of this active energy ray-curable polymer was measured by the method described later, it was 600,000.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, the same applies hereinafter), and 3 parts by mass of 1-hydroxycyclohexylbenzophenone (manufactured by BASF Corporation, product name "IRGACURE 184") as a photopolymerization initiator. 3.11 parts by mass of toluene diisocyanate (manufactured by Tosoh Corporation, product name "CORONATE L") as a crosslinking agent, and mixed in a solvent to obtain an adhesive composition.

(2) Formation of adhesive layer On the release surface of a release sheet (manufactured by Lintec, product name "SP-PET381031") formed by forming a silicone release agent layer on one side of a polyethylene terephthalate film with a thickness of 38 μm, apply The above-mentioned adhesive composition was dried by heating and then aged for 7 days under the conditions of 23° C. and 50% RH to form an adhesive layer with a thickness of 5 μm on the release sheet.

(3) Production of sheets for workpiece processing The surface of the adhesive layer formed in the above step (2) that is opposite to the release sheet is bonded to one side of an ethylene-methacrylic acid copolymer (EMAA) film with a thickness of 80 μm as a substrate to obtain Sheets for workpiece processing.

Here, the said weight average molecular weight (Mw) is the weight average molecular weight of standard polystyrene conversion measured using gel permeation chromatography (GPC) (GPC measurement).

[Examples 2 to 5 and Comparative Examples 1 to 3] Except having changed the composition of an acryl-type copolymer as shown in Table 1, and having changed content of a crosslinking agent as shown in Table 2, it carried out similarly to Example 1, and manufactured the sheet|seat for workpiece|work processing.

[Test Example 1] (Measurement of Oxygen Atomic Ratio) The release sheet was peeled off from the workpiece processing sheets produced in Examples and Comparative Examples, and the oxygen atomic ratio (%) of the exposed surface (adhesive surface) of the exposed adhesive layer and the depth of 100 nm from the exposed surface were measured. The atomic ratio (%) of oxygen in the adhesive layer at the position of 0 was measured using an X-ray photoelectron spectrometer (manufactured by ULVAC-PHI, product name "PHI Quantera SXM"), and each was defined as the "position of 0 nm". Oxygen atom ratio (%), and oxygen atom ratio (%) of "position of 100nm". The results are shown in Table 3.

[Test Example 2] (Measurement of Water Contact Angle) The release sheet was peeled off from the workpiece processing sheets manufactured in Examples and Comparative Examples, and the water contact angle (°) of the exposed surface of the exposed adhesive layer was measured using a fully automatic contact angle measuring instrument (Kyowa Interface Science Co., Ltd. manufactured under the product name "DM-701"), and measured under the following conditions. The results are shown in Table 3. ‧Amount of purified water droplet: 2μl ‧Measurement time: 3 seconds after dripping ‧Image analysis method: θ/2 method

[Test Example 3] (Measurement of Adhesion) Peel off the release sheet from the workpiece processing sheets produced in the examples and comparative examples, and overlap the exposed surface of the exposed adhesive layer on the mirror surface of a 6-inch silicon wafer after mirror-finishing, and use a 2 kg roller to carry out 1 The load was applied back and forth, and it was bonded, and it was left to stand for 20 minutes. Then, at a peeling speed of 300mm/min and a peeling angle of 180°, the workpiece processing sheet was peeled off from the silicon wafer, and the adhesive force F1 (mN/ 25mm). The results are shown in Table 3.

Furthermore, the peeling sheet was peeled off from the workpiece processing sheet manufactured in the Example and the comparative example, and the exposed surface of the exposed adhesive layer was immersed in 23 degreeC distilled water for 12 hours, and dried at 23 degreeC for 24 hours. Then, this exposed surface was superimposed on the mirror surface of a mirror-finished 6-inch silicon wafer, and a 2 kg roller was used to perform one reciprocation to apply a load and stick together, and left to stand for 20 minutes. Next, peel the workpiece processing sheet from the silicon wafer at a peeling speed of 300mm/min and a peeling angle of 180°, and measure the resistance to the silicon wafer after the above-mentioned immersion and drying according to the 180° peeling method of JIS Z0237:2009. Adhesion F2 (mN/25mm). The results are shown in Table 3.

Furthermore, using the adhesive force F1 (mN/25mm) and adhesive force F2 (mN/25mm) values obtained as above, the following formula (1): Adhesion reduction rate (%)={(F1-F2)/F1}×100…(1) Adhesion reduction rate (%) was calculated. The results are shown in Table 3.

[Test Example 4] (Evaluation of Removability of Adhesive) The adhesive compositions prepared in Examples and Comparative Examples were applied to a release sheet (Lintec Made by the company, product name "SP-PET381031") was dried by heating to form an adhesive layer with a thickness of 5 μm on the release sheet. From the laminated body of the pressure-sensitive adhesive layer and the release sheet thus obtained, 20 small pieces of the laminated body having a size of 5 mm×5 mm were cut out.

Then, on the grinding surface of a 6-inch silicon wafer (thickness: 150 μm) polished by #2000, respectively stick the surface of the adhesive layer side of the 20 small pieces obtained as above, respectively, from the adhesive layer. The peel-off sheet peels off. In this pasting, the small pieces are pasted at intervals of 1 mm or more.

Then, the release sheet was peeled off from the workpiece processing sheets produced in the examples and comparative examples, and a film laminating machine (manufactured by Lintec Corporation, product name "Adwill RAD2500m/12") was used on the exposed surface of the exposed adhesive layer. Paste the side of the above-mentioned 6-inch silicon wafer that is opposite to the side to which the small chip is pasted. Next, using a dicing device (manufactured by Disc Corporation, product name "DFD-6361"), dicing was performed by cutting from the 6-inch silicon wafer side while supplying a water flow to the cutting part under the following operating conditions.

＜Operating conditions＞ ‧Cutting device: DFD-6361 manufactured by Disc Corporation ‧Blade: Disc NBC-2H 2050 27HECC ‧Blade width: 0.025~0.030mm ‧Blade extension: 0.640~0.760mm ‧Blade rotation speed: 50000rpm ‧Cutting speed: 20mm/sec ‧Blade height: 5mm ‧Water flow supply: 1.0L/min ‧Water flow temperature: room temperature ‧Cutting size: 10mm×10mm In addition, the above-mentioned "blade height: 5 mm" means that the distance between the blade and the 6-inch silicon wafer is set to 5 mm. From this, it can be seen that the above-mentioned operation does not use the blade to cut the 6-inch silicon wafer.

After dicing, it was confirmed whether or not the adhesive derived from the above-mentioned small pieces remained on the silicon wafer, and the removability of the adhesive was evaluated according to the following criteria. The results are shown in Table 3. ◯: The adhesive does not remain at all. ×: At least a part of the adhesive remains.

[Test Example 5] (Evaluation of Water Penetration) The release sheet was peeled off from the workpiece processing sheet produced in the examples and comparative examples, and the exposed surface of the adhesive layer was pasted using a film applicator (manufactured by Lintec, product name "Adwill RAD2500m/12"). #2000 polished surface of 6-inch silicon wafer (thickness: 150μm). Next, using a dicing device (manufactured by Disc Corporation, product name "DFD-6361"), dicing was performed by cutting from a 6-inch silicon wafer while supplying a water flow to the cutting part under the following dicing conditions.

＜Cutting conditions＞ ‧Cutting device: DFD-6361 manufactured by Disc Corporation ‧Blade: Disc NBC-2H 2050 27HECC ‧Blade width: 0.025~0.030mm ‧Blade extension: 0.640~0.760mm ‧Blade rotation speed: 50000rpm ‧Cutting speed: 20mm/sec ‧Incision depth: 15μm from the surface of the adhesive layer side of the workpiece processing sheet ‧Water flow supply: 1.0L/min ‧Water flow temperature: room temperature ‧Cutting size: 10mm×10mm

After dicing, remove all the obtained wafers from the workpiece processing sheet, and observe the adhesive in the workpiece processing sheet with a digital microscope (manufactured by KEYENCE Corporation, product name "VHX-1000", magnification: 500 times) The surface on the layer side was evaluated for water penetration into the interface between the wafer and the workpiece processing sheet according to the following criteria. The results are shown in Table 3. ○: There is no trace of water penetration on the surface of the sheet for workpiece processing on the side of the adhesive layer. ×: There are traces of water infiltration on the surface of the adhesive layer side in the sheet for workpiece processing.

In addition, the details of the abbreviations etc. listed in Table 1 are as follows: BA: butyl acrylate MMA: methyl methacrylate DMAA: Dimethacrylamide MA: methyl acrylate 2MEA: 2-methoxyethyl acrylate MTG: Methoxyethylene glycol acrylate HEA: 2-hydroxyethyl acrylate MOI: Methacryloxyethyl isocyanate

[Table 1]

[Table 2]

[table 3]

It can be seen from Table 3 that the sheet for workpiece processing obtained in the examples can well remove the adhesive by using water flow, and can well inhibit the infiltration of water. [Industrial availability]

The sheet for workpiece processing of the present invention can be preferably used for cutting.

none.

none.

Claims (10)

A sheet for workpiece processing, which includes: a substrate, and a sheet for workpiece processing with an adhesive layer laminated on one side of the substrate; it is characterized in that, Among the positions in the adhesive layer, at a position at a depth of 100 nm from the surface of the adhesive layer opposite to the substrate, the atomic ratio of oxygen measured by X-ray photoelectron spectroscopy is 20 atomic % or more and 29 atomic % or less. The sheet for workpiece processing according to claim 1, wherein the thickness of the adhesive layer is not less than 1.5 μm and less than 50 μm. The sheet for workpiece processing according to claim 1, wherein the water contact angle of the surface of the adhesive layer opposite to the substrate is 50° or more and 80° or less. The workpiece processing sheet as described in item 1 of the scope of the patent application, wherein the adhesive force of the workpiece processing sheet to the silicon wafer is set as F1; the above workpiece processing sheet is immersed in distilled water at 23°C for 12 hours, and then dried at 23°C for 24 hours, when the adhesive force of the above workpiece processing sheet to the silicon wafer is set as F2, the reduction rate of the adhesive force calculated by the following formula (1) is 20% or more And less than 50%, Adhesion reduction rate (%)={(F1-F2)/F1}×100...(1). The sheet for workpiece processing as described in claim 4 of the claims, wherein the above-mentioned adhesive force F1 is not less than 1000 mN/25mm and not more than 10000 mN/25mm. The sheet for workpiece processing as described in claim 4 of the claims, wherein the above-mentioned adhesive force F2 is not less than 900 mN/25mm and not more than 8000 mN/25mm. The workpiece processing sheet according to claim 1, wherein the adhesive layer is composed of an active energy ray-curable adhesive. The sheet for workpiece processing according to Claim 7 of the patent claims, wherein the above-mentioned active energy ray-curable adhesive is an adhesive formed of an adhesive composition containing an acrylic copolymer, and the acrylic copolymer contains At least one selected from methyl acrylate, 2-methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, and methoxyethylene glycol (meth)acrylate as a constituent The monomeric unit of a polymer. The workpiece processing sheet as described in claim 1 of the patent application is a dicing sheet. A method of manufacturing a finished workpiece, characterized by comprising: A bonding step, which is to bond the surface of the adhesive layer on the opposite side to the base material of the sheet for workpiece processing as described in any one of claims 1 to 9 of the patent application to the workpiece; A processing step of obtaining a processed workpiece laminated on the above-mentioned workpiece-processing sheet by processing the above-mentioned workpiece on the above-mentioned workpiece-processing sheet; an irradiating step of irradiating the adhesive layer with active energy rays to harden the adhesive layer and reduce the adhesive force of the workpiece processing sheet to the processed workpiece; and The separation step is to separate the above-mentioned processed workpiece from the above-mentioned workpiece processing sheet after the active energy ray irradiation.